DESCRIPTION: This represents a far ranging proposal to explore molecular mechanisms of regulation in yeast by one of the founders of yeast molecular biology. The four tangentially related objectives are: 1) post- translational control of the S. cerevisiae GCN4 gene; 2) regulation of intracellular levels of amino acids, particularly histidine, in S. cerevisiae; 3) probing for existencing of a multicopy silencing system in S. cerevisiae; and 4) testing for evidence of a meiotic cycle in C. albicans.